The title says it all. I know that 'complex' is a pretty ambiguous term to use, but I can't think of a more scientific term/definition for my meaning. I can't think of any large (larger then a small ...

What form of reproduction did the first animals on land use*? Were they hermaphrodites, or did they have male and female sexes? [Is there a proper term for sexual separation in a species?]
Were any ...

When we have a sex with partner, we feel so tired that we don't have any power to do anything. Then it would be disadvantage to the animals, of course humans too, for they are exposed to danger. For ...

From what I understand in the alternation of generations in ferns, mature spores germinate into a haploid prothallium. But how does this gametophyte produce recombinant gametes if it itself develops ...

Homo sapiens have menopause - as some other mammals (e.g. some Cetacea) - a phenomenon where older females live for decades after the end of their own reproduction.
Perhaps homosexuality, that looks ...

As long as we only look at humans the differences are clear: males have chromosomes XY, produce sperm and don't get pregnant. Females have chromosomes XX, produce egg cells and bear babies. But when ...

I am very new at this. I am wondering why fed batch cultures produce a lot of mycelia but no fruit. I thought the more mycelia you had, the greater chance of it forming a fruit body.
I am refering to ...

(Apologies if this is a too weird/inappropriate question in this forum. I only thought that I ask it since it happens to be part of human life.)
The skin on a human typically blocks many substances ...

Why it is difficult to control orgasm in male humans? How are orgasms controlled and what is different between males and females?
We can control urine for few minutes, but we can't control orgasm for ...

There are obviously good reasons that explain why you cannot tickle yourself (see e.g. here). This got me thinking why it is possible to masturbate...
Wouldn't it make more sense to not being able to ...

I wonder why (especially human) sex lasts longer than just a few seconds?
My thought is that the shorter it takes a man to ejaculate, the lesser is the risk that he gets interrupted by a rival or a ...

Gynodioecy is when a population features individuals that produce both male and female gametes and individuals that produce just female gametes. Androdioecy is when a population features individuals ...

Is the result of meiosis ONLY the sex gametes (male and female) which later meet to form a somatic cell?
Sometimes I feel as if my book is hinting towards meiosis is the process where sperm cells meet ...

In general, for dioecious species, a large portion of the genome passed from parents to offspring of both sexes - in mammals the X-chromosomes and autosomes are passed from a mother to both daughters ...

I observerd myself and I can identify two different types of "happines".
First - called by me - After Pleasure :
Occurs AFTER (and last long) long activity that require from me engagement focus and ...

There are several sex determining systems in animals.
In mammals XY = male(except in rare cases where SRY crosses with genes on the X so that it is the reverse) and XX = female.
In some birds it is ...

Are there any advantages of bisexual reproduction over asexual one towards species conservation and promotion? Do animals that have two or more sexes have more chances to reproduce?
Does anybody had a ...

The diploid chromosomal architecture is rather interesting. For example, because of diploidy we Humans have to mate. Of course in that sense, because diploid organisms often have mate, this has led to ...

In monoecious plants having unisexual flowers (eg Zea Mays, Ricinus Communis etc), there must be some mechanism as to produce two sexually distinct flowers from the same genotype. Since both the type ...

Imagine a lineage of multicellular organisms that had mating types and evolved their mating types into sexes. What are the possible mechanisms that might have brought this lineage to evolve sexes from ...

This question is a follow-up to
this one.
I've been wondering how small that probability is. As we all know, "safe" sex, that is (correctly) using a condom and all that, isn't perfectly safe. So, in ...

The wikipedia article on human height reports mean height for many different countries by sex but it does not report standard deviations.
What is the standard deviation of adult human heights within ...

I know that a minority of plants are fully dioecious, with adult plants producing either only male or only female flowers. When is this sexual differentiation determined? Is the seed of such a plant ...

I heard that some monkeys can be homosexual? a friend of mine was saying that he saw a male monkey having sex with another male monkey in the zoo, I honestly didn't believe him, I think he just got ...

The majority of animals have two genders, and both are needed in reproduction. It seems like it would be more advantageous for creatures to be hermaphrodites, since they could mate with any member of ...